Economists cautioned that families are reluctantly reaching into savings or skipping the bank altogether to keep up with higher bills, blamed mostly on rising gas- pump and food prices.

About half of February’s inflation was based solely on gas-pump and food increases, the Federal Reserve said.

The Fed said inflation rose 0.4 percent in February — the biggest monthly jump in nearly three years — for an annual pace of 3.6 percent. Excluding food and energy prices, inflation in February was just half that, 0.2 percent, or an annual 2.4 percent.

Until now, spending had been riding at its highest pace in more than four years at an annual rate of 4 percent by the end of 2010, pushing the economic growth rate to 3.1 percent.

Higher price burdens and weak incomes are likely to knock down the spending rate to a paltry 2 to 2.5 percent for the first quarter, and drag down the economy’s growth rate to between 2.5 and 3.5 percent.

“Consumer spending is going to come in weaker relative to what the consensus is expecting, and that in turn means the growth expectations are too high. But it doesn’t mean that the consumer is going to roll over,” said economist Neil Dutta at Bank of America Merrill Lynch.

Savings in February fell to an annual rate of $676.7 billion from $710.5 billion in January, or a drop to 5.8 percent of after-tax incomes, from 6.1 percent in January.